1. Field of the Invention
The present invention is broadly concerned with improved apparatus for scoring and slotting of cardboard sheets in order to form box blanks. More particularly, it is concerned with such apparatus which can be readily retrofitted on existing, old style equipment, while also permitting extremely rapid and accurate makeready adjustments of the slotting knives of the apparatus and the sheet feeding assembly thereof.
2. Description of the Prior Art
Box-making plants universally make use of large equipment designed for the high speed fabrication of box blanks from starting cardboard sheets. In general, these machines are operable to individually feed cardboard sheets from a stack thereof into a scoring and slotting assembly wherein the sheets are appropriately scored and slotted to form the side panels and end flaps required for box blanks. The scoring and slotting assembly in turn includes two pairs of side-by-side shafts. One shaft pair carries a plurality of laterally spaced apart scoring wheels and cooperating anvils for forming continuous score lines in the incoming sheets. The adjacent shaft pair carries a similar plurality of adjustable and continuous slotting wheels which form the flap-defining slots in the box blank.
Machines of this character operate with good efficiency once they are properly adjusted, i.e., the fixed and adjustable knives of the slotting wheels are properly positioned relative to each other and in conjunction with the sheet feeding assembly of the machine. However, once a particular production run has been completed, it is often necessary to adjust the lateral and circumferential positions of the scoring/slotting stations and the fixed and adjustable knives thereof. Moreover the initial or zero position of the feeding assembly must be adjusted to accept a different size of starting sheet. Such adjustments have heretofore required the machine operator to manually change the feeder assembly zero position, and to alter the positions of at least the adjustable knives of the slotting wheels. The latter requires that the operator individually change each knife, in the crowded confines of the machine. This is not only time-consuming and difficult, but can lead to inaccuracies if the knives are not precisely repositioned. Indeed, makeready changeovers of this character can often take twenty minutes or more, which represents a significant down time for the equipment, particularly where a number of the changeovers are required on a daily basis.
U.S. Pat. No. 4,090,433 describes a scoring/slotting apparatus provided with dual compensators for facilitating the rapid adjustment of the fixed and movable knives of such apparatus. However, the structural arrangement described in this patent does not lend itself to ready retrofitting of existing equipment. This is a prime deficiency, inasmuch as the box making industry has a substantial investment in its existing equipment, and would be loathe to invest in wholly new scoring/slotting apparatus simply to obtain faster makeready capability.